A Viscoelastic Correspondence Principle for Plane Membranes Subjected to Lateral Pressure

1983 ◽  
Vol 50 (4a) ◽  
pp. 740-742 ◽  
Author(s):  
B. Stora˚kers
Keyword(s):  
Time Dependence ◽  
Viscoelastic Material ◽  
Lateral Pressure ◽  
Correspondence Principle ◽  
Material Model ◽  
Material Behavior ◽  
Linear Elastic Material ◽  
First Order ◽  
Linear Elastic ◽  
Consistent Approximation

The classical Fo¨ppl equations, governing the deflection of plane membranes, constitute the first-order consistent approximation in the case of linear elastic material behavior. It is shown that despite the static and kinematic nonlinearities present, for arbitrary load histories a correspondence principle for viscoelastic material behavior exists if all relevant relaxation moduli are of uniform time dependence. Application of the principle is illustrated by means of a popular material model.

Variation Principles and Bounds for the Approximate Analysis of Plane Membranes Under Lateral Pressure

1983 ◽  
Vol 50 (4a) ◽  
pp. 743-749 ◽  
Author(s):  
B. Stora˚kers
Keyword(s):  
Lateral Pressure ◽  
Practical Interest ◽  
Upper Bounds ◽  
Approximate Analysis ◽  
Lower And Upper Bounds ◽  
First Order ◽  
Linear Elastic ◽  
Consistent Approximation ◽  
Elastic Membranes ◽  
Variational Formulations

A first-order consistent approximation for the analysis of small deflections of membranes is given several variational formulations. Lower and upper bounds are derived for the volume enclosed by deformed and undeformed membranes. The power of the principles is discussed and their application is illustrated by some cases of practical interest. Explicit analytical results are given for linear elastic membranes having circular, elliptic, and rectangular contours.

A Microstructure-Level Material Model for Simulating the Machining of Carbon Nanotube Reinforced Polymer Composites

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Ashutosh Dikshit ◽  
Johnson Samuel ◽  
Richard E. DeVor ◽  
Shiv G. Kapoor
Keyword(s):  
Carbon Nanotube ◽  
Weight Fraction ◽  
Material Model ◽  
Material Behavior ◽  
Compression Tests ◽  
Linear Elastic ◽  
Rate Dependent ◽  
Wide Range ◽  
Parametrization Scheme ◽  
Fraction Length

A continuum-based microstructure-level material model for simulation of polycarbonate carbon nanotube (CNT) composite machining has been developed wherein polycarbonate and CNT phases are modeled separately. A parametrization scheme is developed to characterize the microstructure of composites having different loadings of carbon nanotubes. The Mulliken and Boyce constitutive model [2006, “Mechanics of the Rate Dependent Elastic Plastic Deformation of Glassy Polymers from Low to High Strair Rates,” Int. J. Solids Struct., 43(5), pp. 1331–1356] for polycarbonate has been modified and implemented to capture thermal effects. The CNT phase is modeled as a linear elastic material. Dynamic mechanical analyzer tests are conducted on the polycarbonate phase to capture the changes in material behavior with temperature and strain rate. Compression tests are performed over a wide range of strain rates for model validation. The model predictions for yield stress are seen to be within 10% of the experimental results for all the materials tested. The model is used to study the effect of weight fraction, length, and orientation of CNTs on the mechanical behavior of the composites.

Simulation of Fatigue Crack Growth Using XFEM

2020 ◽  
Author(s):  
Durlabh Bartaula ◽  
Yong Li ◽  
Smitha Koduru ◽  
Samer Adeeb
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Elastic Material ◽  
Low Cycle Fatigue ◽  
Material Behavior ◽  
Plastic Behavior ◽  
Linear Elastic Material ◽  
Linear Elastic ◽  
Cyclic Approach

Abstract Pipelines carrying oil and gas are susceptible to fatigue failure (i.e., unstable fatigue crack propagation) due to fluctuating loading such as varying internal pressure and other external loadings. Fatigue crack growth (FCG) prediction through full-scale pipe tests can be expensive and time consuming, and experimental data is limited particularly in the face of large uncertainty involved. In contrast, numerical simulation techniques (e.g., XFEM) can be alternative to study the FCG, given that numerical models can be theoretically and/or experimentally validated with reasonable accuracy. In this study, capabilities and limitations of existing fatigue analysis code (e.g., direct cyclic approach with XFEM) in Abaqus for low cycle fatigue simulation are explored for compact-tension (CT) specimens and pipelines assuming linear elastic material behavior. The simulated FCG curve for a CT specimen is compared with that obtained from the analytical method using the stress intensity factor prescribed in ASTM E647. However, for real pipelines with elastic-plastic behavior, direct cyclic approach is not suitable, and an indirect cyclic approach is used based on the fracture energy parameters (e.g., J integral) calculated using XFEM in Abaqus. FCG law (e.g., power law relationship like Paris law) is used to generate the fatigue crack growth curve. For comparison, the FCG curve obtained through direct cyclic approach for pipelines assuming linear elastic material is also presented. The comparative studies here indicate that XFEM-based FCG simulation using appropriate techniques can be applied to pipelines for fatigue life prediction.

Determination of Fracture Toughness for Metal/Polymer Interfaces

1999 ◽  
Vol 121 (4) ◽  
pp. 275-281 ◽  
Author(s):  
V. Sundararaman ◽  
S. K. Sitaraman
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Release Rate ◽  
Critical Energy ◽  
Material Behavior ◽  
Finite Element Analyses ◽  
Critical Energy Release Rate ◽  
Linear Elastic Material ◽  
Linear Elastic ◽  
Metal Polymer

This work focuses on the interpretation of experimental results obtained from fracture toughness tests conducted for a typical metal/polymer bimaterial interface similar to those encountered in electronic packaging applications. Test specimens with pre-implanted interfacial cracks were subjected to a series of fracture toughness tests. Interfacial fracture toughness is interpreted from the experimental results as the critical energy release rate (Gc) at the instant of crack advance. The values of Gc from the experiments are determined using direct data reduction methods assuming linear elastic material behavior. These Gc values are compared to critical energy release rate values predicted by closed-from analyses of the tests, and to critical J-integral values obtained from finite-element analyses of the test specimen geometries. The closed-form analyses assume linear elastic material behavior, while the finite-element analyses assume both linear elastic as well as elastic-plastic material behaviors.

Application of a Fractional Viscoelastic Material Model to Rubber in Comparison to a Linear Approach

2017 ◽  
Author(s):  
Michael Burgwitz ◽  
Johan Steffen Bothe ◽  
Matthias Wangenheim
Keyword(s):  
Viscoelastic Material ◽  
Thermoplastic Polyurethane ◽  
Material Model ◽  
Material Behavior ◽  
Constitutive Law ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Linear Approach ◽  
Important Challenge ◽  
Linear Viscoelastic

The modeling of material behavior is an important challenge in structural dynamics. While some materials can be well represented by a linear constitutive law, this becomes more complex when dealing with viscoelastic components. In this paper we investigate a fractional viscoelastic material model and present our results of research, focusing on its parametrical characteristics. We compare the results to a classical linear viscoelastic standard model and highlight advantages of the particular approach: we conduct monofrequent sinusoidal excitations using a DMTA (Dynamic Mechanic Thermal Analysis) machine. We use a viscoelastic TPU (Thermoplastic Polyurethane) sheet as sample and apply varying excitation frequencies and amplitudes. In a first modeling step we reproduce the experimental results with a fractional single degree-of-freedom system with promising results.

scholarly journals Finite Element modeling of Mechanical Loading-Pumpkin Peel and flesh

2017 ◽  
Vol 13 (5) ◽  
Author(s):  
Maryam Shirmohammadi ◽  
Prasad KDV Yarlagadda
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Plastic Material ◽  
Material Model ◽  
Mean Square ◽  
Fe Modeling ◽  
Material Models ◽  
Linear Elastic Material ◽  
Error Indicator ◽  
Linear Elastic

Abstract Finite element (FE) models of uniaxial loading of pumpkin peel and flesh tissues were developed and validated using experimental results. The tensile model was developed for both linear elastic and plastic material models, the compression model was developed only with the plastic material model. The outcomes of force versus time curves obtained from FE models followed similar pattern to the experimental curves; however the curve resulted with linear elastic material properties had a higher difference with the experimental curves. The values of predicted forces were determined and compared with the experimental curve. An error indicator was introduced and computed for each case and compared. Additionally, Root Mean Square Error (RMSE) values were also calculated for each model and compared. The results of modeling were used to develop material model for peel and flesh tissues in FE modeling of mechanical peeling of tough skin vegetables. The results presented in this paper are a part of a study on mechanical properties of agricultural tissues focusing on mechanical peeling methods using mathematical, experimental and computational modeling.

On the Dynamic Response of a Single-Degree-of-Freedom Structure Attached to the Interior of a Rotating Rigid Ring

1988 ◽  
Vol 55 (1) ◽  
pp. 201-205 ◽  
Author(s):  
A. G. Hernried ◽  
G. B. Gustafson
Keyword(s):  
Dynamic Response ◽  
Constant Angular Velocity ◽  
Degree Of Freedom ◽  
Material Behavior ◽  
Dynamic Features ◽  
Single Degree Of Freedom ◽  
Rigid Ring ◽  
Linear Elastic Material ◽  
Linear Elastic ◽  
Single Degree

The dynamic response of a single-degree-of-freedom structure attached to the interior of a rigid ring that is rotating with constant angular velocity is investigated. It is assumed that the deformations of the structure from the undeformed configuration are small, and that the structure exhibits linear elastic material behavior. Both undamped and viscously damped structures are considered. Inclusion of all of the essential dynamic features of the problem (notably Coriolis effects) results in a nonlinear differential equation governing the response of the attached structure. Numerical and analytical studies are performed on the nonlinear governing equation to determine the response and stability of the structure.

scholarly journals NUMERICAL MODELLING OF THE SOIL BEHAVIOUR BY USING NEWLY DEVELOPED ADVANCED MATERIAL MODEL

2017 ◽  
Vol 57 (1) ◽  
pp. 58-70 ◽  
Author(s):  
Jan Veselý
Keyword(s):  
Numerical Modelling ◽  
Plastic Material ◽  
Material Model ◽  
Small Strain ◽  
Theoretical Background ◽  
Linear Elastic ◽  
In Situ Data ◽  
Modified Cam Clay ◽  
Soil Behaviour

This paper describes a theoretical background, implementation and validation of the newly developed Jardine plastic hardening-softening model (JPHS model), which can be used for numerical modelling of the soils behaviour. Although the JPHS model is based on the elasto-plastic theory, like the Mohr-Coulomb model that is widely used in geotechnics, it contains some improvements, which removes the main disadvantages of the MC model. The presented model is coupled with an isotopically hardening and softening law, non-linear elastic stress-strain law, non-associated elasto-plastic material description and a cap yield surface. The validation of the model is done by comparing the numerical results with real measured data from the laboratory tests and by testing of the model on the real project of the tunnel excavation. The 3D numerical analysis is performed and the comparison between the JPHS, Mohr-Coulomb, Modified Cam-Clay, Hardening small strain model and monitoring in-situ data is done.

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